On August 29, astronauts on the ISS awoke to discover a leak on the space station was causing it to lose oxygen.
The six people on the ISS hurried to find the minute hole before they ran out of air.
It was originally thought the leak, which was quickly discovered and sealed, was caused by a tiny meteor which hit the ISS.
A special commission from the Russian State Space Corporation Roscosmos found that the hole was made from the inside, and not the outside – ruling out any impacts from space debris.
Roscosmos, the Russian space agency, now believes the hole was made on purpose.
It also found drill traces near the hole.
Dmitry Rogozin, the head of Roscosmos, said following the findings of an investigation: “It concluded that a manufacturing defect had been ruled out which is important to establish the truth.”
The next stage of the investigation is to discover whether the hole was made on Earth or in space and then find those responsible.
Mr Rogozin added: “Where it was made will be established by a second commission, which is at work now.”
Drew Feustel, current commander of the ISS said it was “a shame and somewhat embarrassing” that some people speculated the leak may have been an act of sabotage by a crew member.
The investigation is set to increase tensions between Roscosmos and NASA, with Mr Rogozin having already previously claimed that it is difficult for the two to space agencies work together.
He said last month: “Problems with NASA, of course, have appeared, but not through the fault of NASA, but through the fault of those American circles outside of NASA.”
Mr Rogozin added the US space agency is dealing with external pressure from “rabid Russophobes.”
But following the discovery of a leak on the ISS, the heads of the space agencies, Mr Rogozin and NASA Administrator Jim Bridenstine, joined forces to establish a solution.
They said in a joint statement: “The Administrator and the General Director noted speculations circulating in the media regarding the possible cause of the incident and agreed on deferring any preliminary conclusions and providing any explanations until the final investigation has been completed.
“They affirmed the necessity of further close interaction between NASA and Roscosmos technical teams in identifying and eliminating cause of the leak, as well as continuation of normal ISS operations and NASA’s ongoing support of the Roscosmos-led Soyuz investigation.
“They acknowledged the entire crew is dedicated to the safe operation of the station and all docked spacecraft to ensure mission success.”